Why does a multiplied texture with alpha loose detail information?
Setting the Blend Mode to multiply isn't necessary. 

Material Settings:


Specular


Intensity: 0.0 


removes this: 
Transparency: On 


Method: Z Transparency
Alpha Slider 0.0



Texture Settings:


Type: Image or Movie
Image: The Texture Image
Use Alpha: On (Otherwise darker parts of the image which are supposed to be opaque will be partially transparent)
Image Sampling


Alpha: Use : On (Otherwise darker parts of the image which are supposed to be opaque will be partially transparent)                   

Mapping


Coordinates: UV
Map: UVMap

Influence


Color: On (1.0)
Alpha: On (1.0)

Blend: Mix (Default)


Settings to compare:




Result (left rendered, right image editor)
Image source by Luc Viatour / www.Lucnix.be



Result zoomed